1. Field of the Invention
This invention relates in general to wellhead assemblies and in particular to providing fluid pressure to a control line through connected passages in a tubing hanger and a wellhead housing.
2. Description of the Prior Art
In oil and gas wells where the wellhead is located at surface level, a tubing hanger will land within a tubing head. The-tubing hanger is located at the upper end of one or more strings of tubing through which production fluids will pass. A passage is typically provided in the tubing hanger to accommodate a control line that may be provided for control of a sub-surface safety valve or other downhole equipment. The valve must have fluid pressure applied to keep the valve open, and the pressure needs to be monitored to ensure the valve remains in an open position.
In related art applications, a control line passage is formed in a tubing hanger and is substantially parallel to the longitudinal axis of the tubing hanger. For small bore tubing heads, this arrangement results in an undesirable sharp right angle bend of the control tubing. The passage would extend completely through the hanger, and lines would connect to the bottom and to the top. The top line has to be coiled and passed out through a port in the wellhead.
A device is provided for controlling and monitoring the fluid pressure to downhole equipment. A tubing hanger is provided with an internal vertical passage. A hydraulic line connects to the lower end of the vertical passage and runs downhole. The vertical passage communicates with a lateral passage through the outer wall of the hanger. A lateral passage through the wellhead housing is generally aligned with the lateral passage of the hanger when the hanger is installed in the wellhead housing. A pressure shaft is installed in the wellhead passage and has a passage therethrough. A seal member having spherical ends is inserted between spherical receptacles located on the inner end of the pressure shaft passage and on the outer end of the lateral passage of the hanger. The seal member has an internal passage having a flared inner end. The seal member is allowed to rotate to sealingly connect the lateral passages, though some misalignment of the lateral passages exists. A gage or other pressure monitoring device or a source of hydraulic pressure can be attached to the outer end of the pressure shaft to communicate with the shaft passage.